Recently, as image forming apparatuses have become multifunctional, systems have become complicated, resulting in a tendency to increase the time period for startup of software. To solve this problem, a technique for reducing a time period for startup of software has been established. In this technique, when the power supply switch of an image forming apparatus is turned off, only a DRAM is energized. After that, when the power supply switch is turned on, the state is changed from the state in which only the DRAM is energized to the previous state before the power supply switch was turned off (hereinafter, referred to as DRAM energization startup).
For example, as described in PTL 1, a technique for reducing a time period for startup of software is established. In this technique, when the power supply switch of an image forming apparatus is turned off, a DRAM image is stored in a nonvolatile storage area (for example, a hard disk). When the power supply switch is turned on, this image is loaded to a DRAM and the previous state before the power supply switch was turned off is restored (hereinafter, referred to as hibernation startup).